The decision whether to insource or outsource IT infrastructure was more complex.
"There was quite a lengthy debate," Amoia recalls.
"The discussions internally were really around risk [and] how quick we could get to the end-state."
Downer paid two vendors (from a pool of five candidates) to participate in what Amoia calls a "blueprint exercise" that would ultimately assist the firm's decision.
"We said, 'Look, what we'd like to do is ... design an environment based on these specifications. We'll pay you for that design, but also give us a proposal to deliver that transformation,'" he says.
"Then we said, 'Well while you're at it, can you also give us a proposal if we were to give you the whole lot and you would run it as well?'
"Because we weren't sure at that time, we were hedging our bets there saying at the end of this process we're either going to choose a vendor to transform our environment and we'd run it, or we would outsource it.
The process ran in parallel with the insource vs. outsource debate. Outsourcing ticked a couple of early boxes for Amoia.
"You've probably heard the term, 'You don't outsource a mess' and I completely agree with that," he says.
"However... I felt I could tick that box because we'd done quite a bit of work around the TCO and because of the blueprint design process that we'd gone through.
"We had a good understanding - as did the two potential partners. So the argument 'you don't outsource a mess' went out the window because I knew what that mess was, I knew what the benefits were going to be and I was happy to tick that box."
Amoia also counted support from Downer's executive body "to make the right decision".
"There was no preference other than make the right decision based on risk and on the commercial aspect," he says.
Ultimately, Amoia says, he was convinced to outsource because it would allow Downer to reach its proposed "end-state" faster.
"We're an organisation that has grown through acquisition and [recently through] organic growth," he says.
"We needed a fairly flexible partner in infrastructure where we could crank up or crank down as the business bought new businesses or divested businesses.
"That was the clincher for me because if I was to try and build that environment myself, I'd be making assumptions ... I wouldn't have all the data to make that decision because the business is looking at investment and divestment options all the time."
The new infrastructure
Downer's IT and network infrastructure is now set to be delivered from HP Enterprise Services' new data centre in Sydney's west.
The firm plans to begin migrating workloads out of eight existing data centres to the single HP facility "around May" on a division-by-division basis.
Data centre consolidation has been on Downer's IT roadmap since mid-2010
"There's no one strategy for that," Amoia says. "There's a number of strategies depending on the data centre."
Cost is a big driver for data centre consolidation ("getting out of expensive data centres we're currently in") as is risk mitigation ("we have servers sitting in rooms they shouldn't be sitting in"), Amoia says.
Amoia says Downer is "buying" availability and response time from HP as part of the outsourced deal, eliminating the need to run an in-house disaster recovery facility.
But reliability of the applications running on that infrastructure remains in Downer's hands, he says.
The new standard server environment uses HP BladeSystem hardware running Microsoft's Hyper-V virtualisation. The company is also using managed network services by HP.
Downer's IT team has conducted some compatibility testing of enterprise apps running on Hyper-V, although Amoia notes "there needs to be more testing".
"We're putting a lot of focus in that now," he says.
Likewise, the company is investing significant time working through licensing agreements for its existing enterprise apps to function in a virtualised environment.
"You need a PhD to work [licensing] out," Amoia jokes. "We're focused on the big ticket [software] items first which are the Microsoft, Oracle and IBM.
"We've pretty much completed that exercise barring a couple of exceptions but we're working through that with the respective vendors."
Read on for Downer's plans for single Active Directory, email and ERP.